According to police a masked thief threw incendiary devices into the building, smashing the large windows on the office level, before fleeing the scene in a getaway vehicle just after midnight yesterday.

Lothian and Borders Police have confirmed they are investigating whether criminal elements could have been attempting to destroy crucial forensic evidence.

The lab is one of the busiest in Scotland, employing 60 highly trained staff and supplying 20 per cent of the total forensic work carried out by all eight Scottish forces.

It deals with around 150 forensic cases each week, and provides toxicology analysis for the whole of Scotland.

Track down

Police are reliant on the specialist work of the SPSA – which has four offices in Scotland – to track down suspects and apprehend them.

While the courts and prosecutors rely on their expert evidence and opinion as evidence to bring them to justice.

Chief Inspector John Rae from Lothian and Borders Police said that the force is not ruling out the possibility that an organised criminal group targeted the lab in an attempt to destroy evidence.

He said: “With regards to anyone attacking that facility, it’s reasonable to suggest that is a possible motive.

“We are certainly not ruling anything out. It is a very unusual crime and a very bold one.

“There is a lot of security in these buildings.

Not vandalism

“It has caught everyone unaware. This is the first attack on any of the forensic labs and it takes a pretty bold attempt.

“We are certainly not looking at it as an act of vandalism – it’s not your average drunk coming out of the pub and putting a brick through the window.”

CI Rae added that the incident is now a “major inquiry”.

He said: “A male was seen making off around the time of the incident, and we would ask any members of the public who saw a fast car in the area at around 00.20am to contact the police.

“The investigation is at a very early stage, we are doing door to door enquiries, we are doing a further search of the area, and forensic teams are in there now.

Support

“Both the premises and modern cities in general have CCTV all over the place, as with any investigation we focus on CCTV and get what we can from that.

“As with any major inquiry we are relying on members of the public to come forward and assist the police.”

SPSA also provides support to forces across Scotland, as well as the Crown Office and the Procurator Fiscal.

Its experts’ primary role is in investigating crime scenes, covering everything from break-ins to murders.

Their specialists are able to analyse DNA and blood traces, and can track down criminals using just a paper tissue or a strand of hair.

Gun

They can also examine firearms to determine how they were used in a crime and can link them to the residue that is left on the skin or sleeve of a culprit when a gun is discharged.

Speaking at the scene of the fire, Tom Nelson, SPSA director of forensic services in Scotland said: “The initial assessment is that no productions have been lost. Two office rooms were fire damaged and the rest of the building suffered smoke damage.

“We spoke to staff this morning and identified some staff who could come in and assist, the rest were told to stay at home.

“We will work to make sure this locus is back up and running again as soon as possible.

“If there are any cases on deadlines involving court dates for example, then we will deal with them as a priority and if they can’t be, we will outsource to other labs in Scotland.

Getaway car

“I am very impressed with the support and professionalism of staff who came in the early hours of this morning to clear up and get it back to normal.”

Detectives are now hunting the masked man – described as 5ft6, of thin build, and wearing a dark top – and the getaway car driver, who fled the scene at high speed in a small dark car.

Last night fire and police officers were still at the scene of the blaze, while forensic officers in white suits worked on both the inside and outside of the building to collect possible clues as to the identities of the suspects.

A spokeswoman for Lothian and Borders Fire and Rescue said: “We attended a two storey building well alight on Howdenhall Road after receiving reports from the police at 00.20am.

Chemical

“Four firefighters entered the building with hose reels. We had three pump appliances on site, as well as an incident command unit and an incident support vehicle and command officers.